Sylvia’s, the legendary soul food restaurant in Harlem, is celebrating its 50th year — by expanding over an entire city block.

Sylvia Woods, known as the “Queen of Soul Food,” died in August at age 86. Her family is honoring her legacy by expanding the business, Side Dish has learned.

The family owns an entire block of Harlem, between 126th and 127th streets on Lenox Avenue.

The lone piece of property not owned by the family is the church, “and we have the first option if they ever decide to move,” said Tren’ness Woods-Black, Woods’ granddaughter.

The family will build more Sylvia’s space in what is now an empty double lot, along with a large events space to hold several hundred people.

“The new facility will be beautiful. It will maintain Sylvia’s Southern charm but with a modern, sleek twist. You will still feel the comfort, Southern soul food vibe,” Woods-Black said.

Sylvia’s started with 35 seats when her mom mortgaged her farm in South Carolina to fund her daughter’s dream in 1962. The restaurant now seats 450 and also has a catering arm and lounge. The addition will hold 175 to 200 more diners.

Diners have included President Clinton, Prince Albert of Monaco and Tony Bennett.

“The good news is that we won’t close during our redevelopment,” Woods-Black said. “We have eight lots altogether, and we will build out in phases.”

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WE HEAR … that Roberta Flack is still killing it softly. After agreeing to serenade anyone who paid $20,000 for a private seven-course dinner party cooked by Chef Ed Brown at last Friday’s Citymeals-on-Wheels “Power Lunch for Women,” Flack was so sought after that the item sold twice: once to Diana Taylor and a second time to Tania Higgins. The event raised more than $1.12 million.